| … | |
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| 132 | .TH "<STANDARD INPUT>" 1 "2007-11-27" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-27" "perl v5.8.8" "User Contributed Perl Documentation" |
| 133 | .SH "NAME" |
133 | .SH "NAME" |
| 134 | libev \- a high performance full\-featured event loop written in C |
134 | libev \- a high performance full\-featured event loop written in C |
| 135 | .SH "SYNOPSIS" |
135 | .SH "SYNOPSIS" |
| 136 | .IX Header "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
| 137 | .Vb 1 |
137 | .Vb 2 |
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|
138 | \& /* this is the only header you need */ |
| 138 | \& #include <ev.h> |
139 | \& #include <ev.h> |
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|
140 | .Ve |
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|
141 | .PP |
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|
142 | .Vb 3 |
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|
143 | \& /* what follows is a fully working example program */ |
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|
144 | \& ev_io stdin_watcher; |
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|
145 | \& ev_timer timeout_watcher; |
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|
146 | .Ve |
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|
147 | .PP |
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|
148 | .Vb 8 |
|
|
149 | \& /* called when data readable on stdin */ |
|
|
150 | \& static void |
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151 | \& stdin_cb (EV_P_ struct ev_io *w, int revents) |
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152 | \& { |
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153 | \& /* puts ("stdin ready"); */ |
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154 | \& ev_io_stop (EV_A_ w); /* just a syntax example */ |
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155 | \& ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
|
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156 | \& } |
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157 | .Ve |
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158 | .PP |
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159 | .Vb 6 |
|
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160 | \& static void |
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161 | \& timeout_cb (EV_P_ struct ev_timer *w, int revents) |
|
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162 | \& { |
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163 | \& /* puts ("timeout"); */ |
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164 | \& ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
|
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165 | \& } |
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166 | .Ve |
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167 | .PP |
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168 | .Vb 4 |
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169 | \& int |
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170 | \& main (void) |
|
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171 | \& { |
|
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172 | \& struct ev_loop *loop = ev_default_loop (0); |
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|
173 | .Ve |
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|
174 | .PP |
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175 | .Vb 3 |
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176 | \& /* initialise an io watcher, then start it */ |
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177 | \& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
|
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178 | \& ev_io_start (loop, &stdin_watcher); |
|
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179 | .Ve |
|
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180 | .PP |
|
|
181 | .Vb 3 |
|
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182 | \& /* simple non-repeating 5.5 second timeout */ |
|
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183 | \& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
|
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184 | \& ev_timer_start (loop, &timeout_watcher); |
|
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185 | .Ve |
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186 | .PP |
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187 | .Vb 2 |
|
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188 | \& /* loop till timeout or data ready */ |
|
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189 | \& ev_loop (loop, 0); |
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190 | .Ve |
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191 | .PP |
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192 | .Vb 2 |
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193 | \& return 0; |
|
|
194 | \& } |
| 139 | .Ve |
195 | .Ve |
| 140 | .SH "DESCRIPTION" |
196 | .SH "DESCRIPTION" |
| 141 | .IX Header "DESCRIPTION" |
197 | .IX Header "DESCRIPTION" |
| 142 | Libev is an event loop: you register interest in certain events (such as a |
198 | Libev is an event loop: you register interest in certain events (such as a |
| 143 | file descriptor being readable or a timeout occuring), and it will manage |
199 | file descriptor being readable or a timeout occuring), and it will manage |
| … | |
… | |
| 240 | might be supported on the current system, you would need to look at |
296 | might be supported on the current system, you would need to look at |
| 241 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
297 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
| 242 | recommended ones. |
298 | recommended ones. |
| 243 | .Sp |
299 | .Sp |
| 244 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
300 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
| 245 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
301 | .IP "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" 4 |
| 246 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
302 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" |
| 247 | Sets the allocation function to use (the prototype is similar to the |
303 | Sets the allocation function to use (the prototype and semantics are |
| 248 | realloc C function, the semantics are identical). It is used to allocate |
304 | identical to the realloc C function). It is used to allocate and free |
| 249 | and free memory (no surprises here). If it returns zero when memory |
305 | memory (no surprises here). If it returns zero when memory needs to be |
| 250 | needs to be allocated, the library might abort or take some potentially |
306 | allocated, the library might abort or take some potentially destructive |
| 251 | destructive action. The default is your system realloc function. |
307 | action. The default is your system realloc function. |
| 252 | .Sp |
308 | .Sp |
| 253 | You could override this function in high-availability programs to, say, |
309 | You could override this function in high-availability programs to, say, |
| 254 | free some memory if it cannot allocate memory, to use a special allocator, |
310 | free some memory if it cannot allocate memory, to use a special allocator, |
| 255 | or even to sleep a while and retry until some memory is available. |
311 | or even to sleep a while and retry until some memory is available. |
| 256 | .Sp |
312 | .Sp |
| 257 | Example: replace the libev allocator with one that waits a bit and then |
313 | Example: replace the libev allocator with one that waits a bit and then |
| 258 | retries: better than mine). |
314 | retries: better than mine). |
| 259 | .Sp |
315 | .Sp |
| 260 | .Vb 6 |
316 | .Vb 6 |
| 261 | \& static void * |
317 | \& static void * |
| 262 | \& persistent_realloc (void *ptr, long size) |
318 | \& persistent_realloc (void *ptr, size_t size) |
| 263 | \& { |
319 | \& { |
| 264 | \& for (;;) |
320 | \& for (;;) |
| 265 | \& { |
321 | \& { |
| 266 | \& void *newptr = realloc (ptr, size); |
322 | \& void *newptr = realloc (ptr, size); |
| 267 | .Ve |
323 | .Ve |
| … | |
… | |
| 707 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
763 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
| 708 | received events. Callbacks of both watcher types can start and stop as |
764 | received events. Callbacks of both watcher types can start and stop as |
| 709 | many watchers as they want, and all of them will be taken into account |
765 | many watchers as they want, and all of them will be taken into account |
| 710 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
766 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
| 711 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
767 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
|
|
768 | .ie n .IP """EV_EMBED""" 4 |
|
|
769 | .el .IP "\f(CWEV_EMBED\fR" 4 |
|
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770 | .IX Item "EV_EMBED" |
|
|
771 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
|
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772 | .ie n .IP """EV_FORK""" 4 |
|
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773 | .el .IP "\f(CWEV_FORK\fR" 4 |
|
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774 | .IX Item "EV_FORK" |
|
|
775 | The event loop has been resumed in the child process after fork (see |
|
|
776 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
| 712 | .ie n .IP """EV_ERROR""" 4 |
777 | .ie n .IP """EV_ERROR""" 4 |
| 713 | .el .IP "\f(CWEV_ERROR\fR" 4 |
778 | .el .IP "\f(CWEV_ERROR\fR" 4 |
| 714 | .IX Item "EV_ERROR" |
779 | .IX Item "EV_ERROR" |
| 715 | An unspecified error has occured, the watcher has been stopped. This might |
780 | An unspecified error has occured, the watcher has been stopped. This might |
| 716 | happen because the watcher could not be properly started because libev |
781 | happen because the watcher could not be properly started because libev |
| … | |
… | |
| 1613 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1678 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
| 1614 | apropriate way for embedded loops. |
1679 | apropriate way for embedded loops. |
| 1615 | .IP "struct ev_loop *loop [read\-only]" 4 |
1680 | .IP "struct ev_loop *loop [read\-only]" 4 |
| 1616 | .IX Item "struct ev_loop *loop [read-only]" |
1681 | .IX Item "struct ev_loop *loop [read-only]" |
| 1617 | The embedded event loop. |
1682 | The embedded event loop. |
|
|
1683 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
|
|
1684 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
|
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1685 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
|
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1686 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
|
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1687 | whoever is a good citizen cared to tell libev about it by calling |
|
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1688 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
|
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1689 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
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1690 | and only in the child after the fork. If whoever good citizen calling |
|
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1691 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
|
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1692 | handlers will be invoked, too, of course. |
|
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1693 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
|
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1694 | .IX Item "ev_fork_init (ev_signal *, callback)" |
|
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1695 | Initialises and configures the fork watcher \- it has no parameters of any |
|
|
1696 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
|
|
1697 | believe me. |
| 1618 | .SH "OTHER FUNCTIONS" |
1698 | .SH "OTHER FUNCTIONS" |
| 1619 | .IX Header "OTHER FUNCTIONS" |
1699 | .IX Header "OTHER FUNCTIONS" |
| 1620 | There are some other functions of possible interest. Described. Here. Now. |
1700 | There are some other functions of possible interest. Described. Here. Now. |
| 1621 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1701 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
| 1622 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
1702 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
| … | |
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| 1791 | \& : io (this, &myclass::io_cb), |
1871 | \& : io (this, &myclass::io_cb), |
| 1792 | \& idle (this, &myclass::idle_cb) |
1872 | \& idle (this, &myclass::idle_cb) |
| 1793 | \& { |
1873 | \& { |
| 1794 | \& io.start (fd, ev::READ); |
1874 | \& io.start (fd, ev::READ); |
| 1795 | \& } |
1875 | \& } |
|
|
1876 | .Ve |
|
|
1877 | .SH "MACRO MAGIC" |
|
|
1878 | .IX Header "MACRO MAGIC" |
|
|
1879 | Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1880 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and |
|
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1881 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
|
|
1882 | .PP |
|
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1883 | To make it easier to write programs that cope with either variant, the |
|
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1884 | following macros are defined: |
|
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1885 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
|
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1886 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
|
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1887 | .IX Item "EV_A, EV_A_" |
|
|
1888 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
|
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1889 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
|
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1890 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
|
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1891 | .Sp |
|
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1892 | .Vb 3 |
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1893 | \& ev_unref (EV_A); |
|
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1894 | \& ev_timer_add (EV_A_ watcher); |
|
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1895 | \& ev_loop (EV_A_ 0); |
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1896 | .Ve |
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1897 | .Sp |
|
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1898 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
|
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1899 | which is often provided by the following macro. |
|
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1900 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
|
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1901 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
|
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1902 | .IX Item "EV_P, EV_P_" |
|
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1903 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
|
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1904 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
|
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1905 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
|
|
1906 | .Sp |
|
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1907 | .Vb 2 |
|
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1908 | \& // this is how ev_unref is being declared |
|
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1909 | \& static void ev_unref (EV_P); |
|
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1910 | .Ve |
|
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1911 | .Sp |
|
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1912 | .Vb 2 |
|
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1913 | \& // this is how you can declare your typical callback |
|
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1914 | \& static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1915 | .Ve |
|
|
1916 | .Sp |
|
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1917 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
|
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1918 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
|
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1919 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
|
|
1920 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
|
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1921 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
|
|
1922 | Similar to the other two macros, this gives you the value of the default |
|
|
1923 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
|
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1924 | .PP |
|
|
1925 | Example: Declare and initialise a check watcher, working regardless of |
|
|
1926 | wether multiple loops are supported or not. |
|
|
1927 | .PP |
|
|
1928 | .Vb 5 |
|
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1929 | \& static void |
|
|
1930 | \& check_cb (EV_P_ ev_timer *w, int revents) |
|
|
1931 | \& { |
|
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1932 | \& ev_check_stop (EV_A_ w); |
|
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1933 | \& } |
|
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1934 | .Ve |
|
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1935 | .PP |
|
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1936 | .Vb 4 |
|
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1937 | \& ev_check check; |
|
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1938 | \& ev_check_init (&check, check_cb); |
|
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1939 | \& ev_check_start (EV_DEFAULT_ &check); |
|
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1940 | \& ev_loop (EV_DEFAULT_ 0); |
| 1796 | .Ve |
1941 | .Ve |
| 1797 | .SH "EMBEDDING" |
1942 | .SH "EMBEDDING" |
| 1798 | .IX Header "EMBEDDING" |
1943 | .IX Header "EMBEDDING" |
| 1799 | Libev can (and often is) directly embedded into host |
1944 | Libev can (and often is) directly embedded into host |
| 1800 | applications. Examples of applications that embed it include the Deliantra |
1945 | applications. Examples of applications that embed it include the Deliantra |
| … | |
… | |
| 2020 | defined to be \f(CW0\fR, then they are not. |
2165 | defined to be \f(CW0\fR, then they are not. |
| 2021 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
2166 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
| 2022 | .IX Item "EV_STAT_ENABLE" |
2167 | .IX Item "EV_STAT_ENABLE" |
| 2023 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
2168 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
| 2024 | defined to be \f(CW0\fR, then they are not. |
2169 | defined to be \f(CW0\fR, then they are not. |
|
|
2170 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
|
|
2171 | .IX Item "EV_FORK_ENABLE" |
|
|
2172 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
2173 | defined to be \f(CW0\fR, then they are not. |
| 2025 | .IP "\s-1EV_MINIMAL\s0" 4 |
2174 | .IP "\s-1EV_MINIMAL\s0" 4 |
| 2026 | .IX Item "EV_MINIMAL" |
2175 | .IX Item "EV_MINIMAL" |
| 2027 | If you need to shave off some kilobytes of code at the expense of some |
2176 | If you need to shave off some kilobytes of code at the expense of some |
| 2028 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
2177 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
| 2029 | some inlining decisions, saves roughly 30% codesize of amd64. |
2178 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2179 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
|
|
2180 | .IX Item "EV_PID_HASHSIZE" |
|
|
2181 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2182 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
|
|
2183 | than enough. If you need to manage thousands of children you might want to |
|
|
2184 | increase this value. |
| 2030 | .IP "\s-1EV_COMMON\s0" 4 |
2185 | .IP "\s-1EV_COMMON\s0" 4 |
| 2031 | .IX Item "EV_COMMON" |
2186 | .IX Item "EV_COMMON" |
| 2032 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2187 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
| 2033 | this macro to a something else you can include more and other types of |
2188 | this macro to a something else you can include more and other types of |
| 2034 | members. You have to define it each time you include one of the files, |
2189 | members. You have to define it each time you include one of the files, |
